Flink无法序列化scala类/任务不可序列化

Question

我有一个scala类，它有两个字段是val，但flink说它没有setter。因此，任务不可序列化。

我尝试使用 var 设置器，但随后它说重复设置器。Vals是公开的，那么为什么它要求二传手。Flink 版本 1.1.0

class Impression(val map: Map[String, String],val keySet:Set[String])

我的代码：

  val preAggregate = stream
.filter(impression => {
    true
})
 .map(impression => {
  val xmap = impression.map
  val values = valFunction(xmap)
  new ImpressionRecord(impression, values._1, values._2, values._3)
})

例外情况：

**class Impression does not contain a setter for field map**
19:54:49.995 [main] INFO  o.a.f.a.java.typeutils.TypeExtractor - class Impression is not a valid POJO type
19:54:49.997 [main] DEBUG o.a.flink.api.scala.ClosureCleaner$ - accessedFields: Map(class  -> Set())
Exception in thread "main" **org.apache.flink.api.common.InvalidProgramException: Task not serializable
at** org.apache.flink.api.scala.ClosureCleaner$.ensureSerializable(ClosureCleaner.scala:172)
at )
Caused by: java.io.NotSerializableException: org.apache.flink.streaming.api.scala.DataStream
at java.io.ObjectOutputStream.writeObject0(ObjectOutputStream.java:1183)
at java.io.ObjectOutputStream.defaultWriteFields(ObjectOutputStream.java:1547)
at java.io.ObjectOutputStream.writeSerialData(ObjectOutputStream.java:1508)
at java.io.ObjectOutputStream.writeOrdinaryObject(ObjectOutputStream.java:1431)
at java.io.ObjectOutputStream.writeObject0(ObjectOutputStream.java:1177)
at java.io.ObjectOutputStream.defaultWriteFields(ObjectOutputStream.java:1547)
at java.io.ObjectOutputStream.writeSerialData(ObjectOutputStream.java:1508)
at java.io.ObjectOutputStream.writeOrdinaryObject(ObjectOutputStream.java:1431)
at java.io.ObjectOutputStream.writeObject0(ObjectOutputStream.java:1177)
at java.io.ObjectOutputStream.writeObject(ObjectOutputStream.java:347)
at org.apache.flink.util.InstantiationUtil.serializeObject(InstantiationUtil.java:301)
at org.apache.flink.api.scala.ClosureCleaner$.ensureSerializable(ClosureCleaner.scala:170)
... 18 more

Answer 1

尽量不要直接使用类的字段，而是将其包装在方法中，这样您就可以开始了。